SIMULATION AND COMPARISON OF CASTING PROCESS, SOLIDIFICATION AND CRYSTAL STRUCTURE IN ASTM A36 STEEL

Abstract

This study presents a simulation-based comparison of the casting process, solidification behavior, and crystal structure formation in ASTM A36 structural steel. Finite element and finite difference methods were employed to model thermal gradients, solidification fronts, and microstructural evolution during sand and die casting processes. The simulation was validated against experimental casting trials, with particular attention paid to dendrite arm spacing, grain morphology, and the development of ferrite-pearlite microstructures characteristic of low-carbon structural steels. Results indicate that cooling rate significantly governs grain refinement and crystal orientation, with die casting producing finer equiaxed grains compared to sand casting. Comparative analysis reveals that the solidification sequence directly influences the final mechanical properties, including yield strength, tensile strength, and impact toughness, all of which must meet ASTM A36 requirements. Thermal contraction and residual stress distributions were also evaluated, demonstrating that controlled solidification mitigates hot-tearing defects. The study provides a comprehensive computational framework for optimizing casting parameters to achieve consistent microstructural quality in ASTM A36 components.